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MAZATLAN UNIVALVES : 215 
Tablet 1036 contains asp. with the hole not constricted in 
the middle. 
Tablet 1037 contains a sp. with a circular hole. Nodulous 
ribs strong. Inside white within the muscular scar, and at 
the margin. In other respects like the typical form. It would 
have passed for a distinct species, but for the intermediate 
form quoted above ; and closely resembles F. Barbadensis. 
[272. FissurRELLA BarpapeEnsis, Gimel. 
Patella Barbadensis, Gmel. p. 3729, no. 199: + P. perforata, 
. Gmel. p. 3730, no. 202: + P. porphyrozonias, Gmel. p. 3730; 
Dillw. p. 1061, no. 102: + P. rosea, Gmel. p. 3730; teste 
B. M. Cat. Cub. Moll. p. 33, no. 400. 
Patella perforata, Dillw. Descr. Cat. p. 1558, no. 95. 
Fissurella Barbadensis, Lam. An. s. Vert. vol. vii. p. 595, 
no. 9: et auct. 
Cremides Barbadensis, H. & A. Ad. Gen. i. 446. 
One small specimen of this well known West Indian species 
was found, which might have been taken for an extreme variety 
of F. rugosa, were it not for.an abundance of the Spiroglyphus, 
and a trace of the red coral, both of which are characteristic of 
the Atlantic ocean, and are entirely absent from the genuine 
Mazatlan shells. It is perfectly fresh, and probably came over 
on a pebble as ballast. 
Hab.—Cuba, Sagra.—Barbadoes, Lamarck et auct.—Mazatlan: 
1 small specimen, ? imported in ballast ; E’pool Col. 
Tablet 1038 contains the specimen. | 
273. FissURELLA RUGOSA, Sow. 
F, t. maxime variante ; plerumque costis plus minusve equali- 
bus, interdum nodulosis, interdum quibusdam alteras maxime 
superantibus ; margine valde irregulari, interdum ovali, inter- 
dum elongato, plerumque antice angulato, a costis plus minusve 
crenato ; apertura haud centrali ; seu subcirculart, ovata; seu 
oblonga, medio constrictd ; seu bilobata; seu trilobatd; seu lineari, 
ad extremitates lobata: callositate plus minusve extante, seu 
concolore, seu lined purpurea cincté ; superficie externa rubro- 
olivaced, seu rubra, sew cinerea ; internd virescente, interdum 
rubro plus minusve maculata ; forméd plerumque planatd, inter- 
dum subconicd. 
Conch. oe sp. 66, f. 54,.—Rve. Conch, Icon. pl. 8, £.56. (Diagn. 
auct. 
